1. Field of the Invention
The present invention is related to information handling systems, and more specifically, to reducing power consumption of the information handling system when in various power states.
2. Background of the Related Technology
As the value and use of information continues to increase, individuals and businesses seek additional ways to process and store information. One option available to users is information handling systems. An information handling system generally processes, compiles, stores, and/or communicates information or data for business, personal, or other purposes, thereby allowing users to take advantage of the value of the information. Because technology and information handling needs and requirements vary between different users or applications, information handling systems may also vary regarding what information is handled, how the information is handled, how much information is processed, stored, or communicated, and how quickly and efficiently the information may be processed, stored, or communicated. The variations in information handling systems allow for information handling systems to be general or configured for a specific user or specific use such as financial transaction processing, airline reservations, enterprise data storage, or global communications. In addition, information handling systems may include a variety of hardware and software components that may be configured to process, store, and communicate information and may include one or more computer systems, data storage systems, and networking systems, e.g., computer, personal computer workstation, portable computer, computer server, print server, network router, network hub, network switch, storage area network disk array, RAID disk system and telecommunications switch.
Use of information handling systems in the office and at home have become ubiquitous and are rapidly becoming transparent to users of these information handling systems. More and more information handling systems are being deployed, and the capabilities and sophistication of these information systems have greatly increased in the last few years. With increased numbers, capabilities and sophistication, the electrical power required by these information systems has significantly increased. However, the full capabilities of the information handling systems may only be utilized a very small percentage of the total time that the systems are energized. Heretofore, to save electrical power the information handling system was manually shutdown. However, having to turn on the information handling system before use, and turn off after use was inconvenient or not performed.
New power saving technologies are being implemented in the latest information handling systems, e.g., instantly available personal computers (IAPCs). The Advanced Configuration and Power Interface (ACPI) specification provides a platform-independent, industry-standard approach to operating-system-based power management. The ACPI specification is a key constituent in Operating System Directed Power Management (OSPM). OSPM and ACPI may apply to all classes of information handling systems, e.g., computers, including handheld, notebook, desktop, and servers. In ACPI-enabled information handling systems, the Basic Input/Output System (BIOS), hardware and associated power architecture use a standard approach that enables the software operation system (OS) to manage the entire information handling system in all operational and power state transition situations.
An ACPI enabled OS can put the entire information handling system or parts of it in and out of various “sleep states,” based on user settings and application requests. The sleep states may be invisible to the user, allowing substantial system power savings, but with instant accesses to areas of the information handling system when required. The ACPI specification defines six possible operating states, referred to as S0 to S5, in order of highest to lowest power consumption. The S0-S2 states are high power, the S3 state is low power, and the S4 and S5 states are minimal or no power. Different subsystems in the information handling system may have dedicated power sources that allow each subsystem or group of subsystems to be in various active (S0-S2), standby (S3) or sleep (S4-S5) states so as to maximize overall power savings, i.e., S0—system on; S1—central processing unit (CPU) stopped, not cycling, random access memory (RAM) is refreshed, the system is running is a low-power mode; S3—standby or suspend to RAM, hard drives are spun down and only RAM remains active; S4—hibernation or suspend to disk, all RAM data written to disk,—computer totally inactive; and S5—power to information handling system is off.
The lowest power consumption comes in the sleep states of S4 or S5, where the information handling system is virtually shutdown. However, these deep, power-saving states come with drawbacks. The more circuitry that is shut down to conserve energy, the longer it takes to restore the information handling system to operational status. Power-management challenges arise when these systems transition between these various states. For example, when a system is in an S3 state, in order to go to the S4 state, the system must first go to the S0 state and perform the required tasks before entering the S4 state. This is all performed with the ACPI enabled OS.
Older information handling systems could only rely upon power strips to completely turn power of to the system. This is costly and requires the user to remember to turn off the power strip.
There is a long felt need in the information handling system technologies, e.g., computer industry, to have systems that consume as little power as possible when they are in the S4 or S5 states. This is especially important to companies having large numbers of these systems. In fact, the U.S. government mandates that a system draw no more than two watts of power in the S4 or S5 states. Much of the future purchasing of new equipment quotations will favor low standby power consumption equipment.
Newer information handling systems have added hardware and firmware that allow the BIOS to turn off the various subsystems, e.g., onboard network interface controller (NIC), when going into an S4 or S5 state, for example, by setting a General Purpose Output (GPO) to a specific logic level to gate power to a subsystem. This feature is usually controlled via a “Low Power Mode” setup menu item. Enabling the Low Power Mode feature allows most computer systems to be low power compliant from the factory, but a user can easily take the system out of compliance by changing device driver settings and/or by adding devices to the computer system that draw larger amounts of power in the S4 or S5 states.
Therefore, a problem exists, and a solution is required so as to improve on how an information handling system handles a Low Power Mode setup.